1. Field of the Invention
The present invention relates to an image forming apparatus, an image forming method, and a computer-readable medium. The present invention relates more particularly to an image forming technique for image data when intermediate language generation processing and rendering processing are performed for each predetermined block in outputting the image data.
2. Description of the Related Art
Conventionally, as an image forming method for image data, the so-called scan line model in which image forming processing is performed for each line is available. The scan line model according to the related art will be described later as the background of the present invention.
As a speed-up method for the image forming method based on the scan line model, a technique which achieves a speed-up by sharing predetermined information of a line intermediate language for every line image forming processing has already come into practical use (see Japanese Patent Laid-Open No. 2003-072162).
The speed-up method makes it possible to reduce the frequency of memory access, the bandwidth used for processing, the load of the apparatus, and the influence that the apparatus exerts on other systems. In addition, various speed-up methods such as sharing of the information of a rendering object extending across divided band regions between individual bands have been proposed.
Also, to reduce the number of resources utilized to form an image (mainly the memory usage), a technique of dividing image data into blocks each having a predetermined size, and performing image forming processing has recently come to be used. Such an image forming technique for each block has been proposed. The image forming technique for each block according to the related art will be described later as the background of the present invention.
The case wherein the speed-up method for the image forming method based on the scan line model is applied to the image forming processing for each block will be considered herein. At this time, if it is determined whether speed-up processing is to be applied, based on an edge on a line on a page in the conventional technique, optimum image forming processing for each block often becomes impossible.
For example, in forming an image of a block 1 501 shown in FIG. 6, the block rendering line information of a block rendering line 1 502 takes the form of a block line intermediate language 506. Also, when the above-mentioned speed-up method is applied, the pieces of block rendering line information of the second and subsequent block rendering lines (for example, a block rendering line 503) take the form of a block line intermediate language 507. Note that the combination of the number of closed regions/the number of layers included in each closed region/the layer information remains the same in each block line, so acquisition of block rendering line information can be omitted for the second and subsequent block rendering lines, and their pieces of block rendering line information take the form of the block line intermediate language 507. In this manner, the above-mentioned speed-up method is directly applicable to the block 1 501.
However, in a block 2 601, the block rendering line information of a block rendering line 1 602 takes the form of a block line intermediate language 606. Also, the block rendering line information of a block rendering line 2 603 takes the form of a block line intermediate language 607. Then, the block rendering line 1 602 includes only one closed region, while the block rendering line 2 603 includes two closed regions. Therefore, even if these two block rendering lines are included in an identical-line-information region 2 405 indicated by an edge addition line, the characteristics vary in each individual line within the block upon division into blocks.
Also, in rendering a portion such as a region 701 having high edge addition frequency, shown in FIG. 7, edge addition occurs at relatively high frequency due to the presence of leftmost character information. Note that in rendering a block 3 702, if it is determined that the speed-up method is to be performed using the conventional edge addition lines, the block intermediate language of a block rendering line 1 703 takes the form of a block line intermediate language 710. Similarly, the pieces of block rendering line information of a block rendering line 2 704 and subsequent block rendering lines take the form of the same, block line intermediate language 710. However, upon determination that, for example, an addition line for each line edge is to be applied to the region 701 having high edge addition frequency, it is determined that the speed-up method is inapplicable, and it is, in turn, determined that no block line intermediate language can be omitted.
Further, both the block line intermediate language of block rendering line N in the block 3 702, and that of a block rendering line 1 707 in a block 4 705 take the form of the block line intermediate language 710. However, in the conventional technique in which omission of a block line intermediate language is determined based on whether the same block line intermediate language is to be used for each block rendering line in the sub-scanning direction, the same block line intermediate language as in the last block rendering line cannot be used in the next block rendering line even if the block rendering line 1 707 in block 4 undergoes the same type of rendering as that for the block rendering line information processed last time.
The present invention has been made in consideration of the above-mentioned conventional problem, and provides block image forming processing which can appropriately determine whether data optimization is possible for each block even if image data is divided into blocks, and can be speeded up.